HIMax Programmable Electronic System (PES) at UK Refinery

The first UK installation of HIMax at a major refinery – and an evaluation of HIMA’s ‘XMR’ architecture


As an integral element of safety within the petrochemical industry, safety systems can be implemented in a variety of ways. The vast majority of solutions see the connection of field detectors hard-wired back to a programmable electronic system (PES) which then feeds into a site’s process control system.

Assuming all detectors and associated cabling are completely sound, system availability and reliability are wholly down to the architecture of the PES; and this is something a leading UK petrochemical refinery wished to evaluate when sourcing a safety system. The refinery turned to Hima-Sella; a world-class designer, supplier and integrator of safety, control and automation systems and which has considerable experience in the petrochemical industry. Already familiar with a number of HIMA safety-related products - around which Hima-Sella builds its systems - the refinery’s engineers were invited to HIMA in Germany for an introduction to the HIMax platform.

Intended for large, critical production processes, HIMax was launched in May 2008 and offers protection to SIL 3, which is the highest level achieved with PES-based systems. Like many other safety monitoring platforms, I/O modules are used to interface with field sensors and central processor units (CPUs) which make the top-level decisions. However, what makes HIMax unique is that it employs HIMA’s XMR architecture. Here the ‘MR’ stands for Modular Redundancy and the ‘X’ denotes flexibility in that it can run with up to four CPUs - as opposed to fixed Triple or Quadruple Modular Redundancy (TMR and QMR respectively).

Also, as each CPU is dual (1002D) processor-based, the system can still operate at SIL 3 with just one CPU. Each I/O module within HIMax has its own set of microprocessors, giving it the integrity and diagnostic capabilities to meet SIL 3 requirements. The testing at I/O-level releases the capacity of the CPUs, allowing faster and larger systems to be achieved.

HIMax has virtually unlimited expansion potential, and its underlying XMR architecture means that both hardware and software changes can be achieved without the need for a shutdown. The system is also cited as delivering the lowest probability of fail to danger (PFD); an essential aspect of any safety-critical system.

Impressed with HIMax, and the fact that the system was already being used by other companies for safety systems in mainland Europe, the engineers proceeded with an order, making their application the first use of HIMax in a UK refinery.

HIMA HIMax Programmable Electronic System PES

In order to evaluate HIMax, Hima-Sella was awarded a £130,000 contract in November 2008 to design and commission a SIL-rated gas detection system. The installation included a HIMax PES, two line-of-site (LOS) gas detectors, 13 IR gas detectors and a panel-mounted graphical matrix (indicating detector locations). Also included within the scope of the project, were two field-mounted cameras, supplied as a CCTV system that sends images to the site’s control room via the HIMax panel.

The system went live in late 2009 and is affording the refinery complete peace of mind that it is doing its job whilst being conducive to expansion in the future.

Download Hima-Sella's Safety Systems brochure.

HIMax passess Shell's assessment tests

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